1. Field of the Invention
The present invention relates to a working machine, and more particularly to a computer numeric control (abbreviated as CNC hereinafter) working machine that can be used for machining both ends and the mediate portion of a workpiece.
2. Description of the Related Prior Art
A conventional CNC working machine comprises a chuck for securing one end of a workpiece, and a rotatable cutter blade for machining the other end of the workpiece. However, the conventional CNC working machine cannot be used for machining both ends of the workpiece simultaneously.
The closet prior arts of a working machine are disclosed in U.S. Pat. No. 5,758,554 to Miyano, entitled "MACHINE TOOL AND METHOD FOR MACHINING A LONG-SHAFTED WORKPIECE", and U.S. Pat. No. 5,842,393 to Nagel, entitled "MACHINE TOOL". In the Miyano prior art, it has to use a clamping device in conjunction with two sets of cutter devices so as to machine both ends of the workpiece. In the Nagel prior art, it has to use three sets of clamping devices in conjunction with two sets of cutter devices so that it is necessary to detach the workpiece from the clamping device to machine both ends of the workpiece.